Spell Mastery

Benefit: Each time you take this feat, choose a number of spells that you already know equal to your Intelligence modifier. From that point on, you can prepare these spells without referring to a spellbook.

Normal: Without this feat, you must use a spellbook to prepare all your spells, except read magic.

However, the feat was written before the existence of the alchemist, magus, and witch classes, and it is a perfectly reasonable house rule to allow those classes to select the feat and apply its benefits to an alchemist’s formula book, magus’s spellbook, or witch’sfamiliar.